G, I think you meant pitch. Roll couple is a function of wing dihedral versus wing CL location vertically on the fuse, relative to the thrust line. These are primary. There are some subtle secondary as well.
pitch couple is a function of CG, and wing and stab incidence. These are primary. There are more subtle secondary variables, but getting the primary right will get you practically all the way there.
Correct, Matt. Meant to say that roll coupling can for the most part be mixed out. A little easier than changing the wing dihedral and position.